Pulsed charged-particle beam system

Abstract

Apparatuses and methods for charged-particle detection may include a deflector system configured to direct charged-particle pulses, a detector having a detection element configured to detect the charged-particle pulses, and a controller having a circuitry configured to control the deflector system to direct a first and second charged-particle pulses to the detection element; obtain first and second timestamps associated with when the first charged-particle pulse is directed by the deflector system and detected by the detection element, respectively, and third and fourth timestamps associated with when the second charged-particle pulse is directed by the deflector system and detected by the detection element, respectively; and identify a first and second exiting beams based on the first and second timestamps, and the third and fourth timestamps, respectively.

The invention claimed is: 
     
       1. An apparatus for observing a sample, comprising:
 a deflector configured to form a plurality of deflected charged-particle beams from a primary charged-particle beam comprising a plurality of pulses of charged particles and deflect the plurality of pulses of charged particles to a plurality of probe spots on a sample; 
 a detector configured to detect a plurality of signals from the sample that result from the plurality of pulses interacting with the sample; and 
 a controller configured to correlate a particular detected signal to a particular probe spot on the sample based on a correlation between a time that the particular signal generated from the particular probe spot was detected and a time associated with a time that a particular charged particle pulse forming the particular probe spot was deflected. 
 
     
     
       2. The apparatus of  claim 1 , further comprising a charged-particle source, an acceleration cavity, and a bunching cavity. 
     
     
       3. The apparatus of  claim 2 , wherein the charged-particle source comprises a pulsed radio-frequency source having a source frequency in a range of 100 MHz to 10 GHz. 
     
     
       4. The apparatus of  claim 1 , wherein the deflector comprises one or more charged-particle deflectors, each of the one or more charged-particle deflectors deflecting the plurality of pulses of charged particles based on an operating frequency. 
     
     
       5. The apparatus of  claim 3 , wherein the deflector is synchronized with the charged-particle source such that an operating frequency and the source frequency are related by an equation: 
       
         
           
             
               
                 v 
                 ⁢ 
                 1 
               
               = 
               
                 
                   1 
                   n 
                 
                 ⁢ 
                 
                   ( 
                   
                     v 
                     ⁢ 
                     2 
                   
                   ) 
                 
               
             
           
         
       
       where v1 is the operating frequency, v2 is the source frequency, and n is a positive integer. 
     
     
       6. The apparatus of  claim 1 , further comprising:
 an electron optical system; and 
 a charged-particle beam scanning system configured to scan each of the plurality of deflected pulses of charged particles on the sample. 
 
     
     
       7. The apparatus of  claim 6 , wherein the electron optical system comprises one of a single-lens system or a multiple-lens system. 
     
     
       8. The apparatus of  claim 6 , wherein the controller is further configured to communicate with at least one of the deflector, the charged-particle beam scanning system, and the detector. 
     
     
       9. A method of observing a sample in a multi-beam apparatus, the method comprising:
 forming, using a deflector, a plurality of deflected charged-particle beams from a primary charged-particle beam comprising a plurality of charged-particle pulses; 
 detecting, using a detector, a plurality of signals generated from a plurality of probe spots formed by the plurality of deflected charged-particle beams; 
 obtaining, using a controller, a first timing information related with formation of a deflected charged-particle beam of the plurality of charged-particle beams, and a second timing information related with detection of a signal of the plurality of signals; and 
 associating, using the controller, the signal with the deflected charged-particle beam based on the obtained first and second timing information. 
 
     
     
       10. The method of  claim 9 , wherein a pulsed radio-frequency charged-particle source is configured to generate the plurality of charged-particle pulses having a source frequency in a range of 100 MHz to 10 GHz. 
     
     
       11. The method of  claim 9 , wherein the deflector comprises one or more charged-particle deflectors, each of the one or more charged-particle deflectors forming the plurality of deflected charged-particle beams based on an operating frequency. 
     
     
       12. The method of  claim 10 , wherein the deflector is synchronized with the charged-particle source such that an operating frequency and the source frequency are related by an equation: 
       
         
           
             
               
                 v 
                 ⁢ 
                 1 
               
               = 
               
                 
                   1 
                   n 
                 
                 ⁢ 
                 
                   ( 
                   
                     v 
                     ⁢ 
                     2 
                   
                   ) 
                 
               
             
           
         
       
       where v1 is the operating frequency, v2 is the source frequency, and n is a positive integer. 
     
     
       13. The method of  claim 9 , further comprising focusing the plurality of deflected charged-particle beams on the sample using an electron optical system. 
     
     
       14. The method of  claim 9 , further comprising scanning each of the plurality of deflected charged-particle beams on the sample using a charged-particle beam scanning system. 
     
     
       15. The method of  claim 14 , further comprising communicating, via the controller, with at least one of the deflector, the charged-particle beam scanning system, and the detector.